1) Field of the Invention
The invention, an improved sofa bed structure, is to provide a firm sofa bed structure, which is a bed board as fully opened and is a sofa bed as folded. The bedstead can be fully opened or folded without difficulty. Especially, all the frame pipes of the bedstead are interlocked. Each bedstead can be disassembled as single tubular pipes to reduce the packing volume of the whole structure. It is not only advantageous to product packing or shopping but also reduce the cost for clearing export customs.
2) Description of the Prior Art
The invention, sofa bed structure, of prior of art primarily includes a fixed mattress and back support cushion. A transversally movable or foldable bed board is equipped at the location of seat cushion for a sofa bed, thus one can pull out or unfold a bed board to form a flat bed depending on practical spatial situation. One can also push or fold a bed board to conceal it for the use of a single sofa bed. However, for both of the methods in concealing a bed board by moving a bed board to the bottom of a seat cushion or folding bed board to the top of seat cushion, the majority of a sofa bed is still a structure comprising of a fixed base seat cushion and back support cushion. When it is fully opened, a back support cushion is not extendable as part of a bed board and eventually becomes a head board of a bed and not convenient in usage. Besides, the outlook of the whole product is in a shape of fixed sofa bed. It is huge in volume and not suitable for packing or shipping. It results unnecessary cost for clearing export customs due to greatly increased volume.